1. Field of the Invention
This invention is directed to cutting inserts and, more particularly, to a cutting insert with chip control features used for metalworking operations and a milling cutter using the same.
2. Description of Related Art
The efficiency of a metalworking operation is directly affected by forces upon and the temperature of the cutting edge of a cutting insert and by the production and formation of curled segments, or chips, removed from the workpiece during the cutting operation. Chips may be used to carry away from the workpiece and from the cutting tool heat produced during the cutting operation thereby preventing excess heat build-up that could damage the cutting tool. However, there are optimum sizes for such chips and while a longer chip may carry away more heat, if the chip is too long it may curl back upon itself and become tangled or it may curl back upon and damage the workpiece. Therefore, it is desired to produce chips that effectively remove heat from the cutting tool but do not impart damage to the cutting tool or to the workpiece and to reduce the forces upon and the temperature of the cutting edge.
Typically a cutting insert is mounted within a milling cutter so that a corner of the insert furthest from an axial location surface of a cutter body in which the insert is mounted is the first part of the insert to engage the workpiece. As a result, that corner of the insert experiences significant forces and temperatures and is prone to premature degradation. One symptom of such degradation is the generation of burrs on the workpiece. While this may not affect the functionality of the finished workpiece, in most applications the finished workpiece should be free of burrs. This is particularly important in components used for powertrains. If a burr breaks free from a powertrain component, the lubrication system of the powertrain may become clogged by the burr and may malfunction. Additionally, burrs may damage bearings within the powertrain. Furthermore still, during heat treatment of a workpiece, burrs extending from the workpiece may cause an electrical short in any induction hardening equipment due to the close proximity to the heating coils and the workpiece.
Therefore, a further object of the subject invention is to provide a cutting insert geometry that will minimize degradation of a cutting edge on a cutting insert and will in the process reduce the occurrence of burrs upon the workpiece.
The invention is directed to a milling cutting insert comprising a polygonal body of wear resistant material, wherein the body has a top surface and a bottom surface opposing one another and therebetween a peripheral wall with sides and corners. The intersection of said peripheral wall and said top surface form a cutting edge. The top surface has a groove with a central axis and extends along the entire length of one side. The groove is tapered such that the width of the groove increases continuously along the sides of the insert.
The subject invention is also directed to a face milling cutter adapted to be advanced in a feed direction along a cutter assembly centerline against a workpiece, wherein the assembly is comprised of a milling cutter body and an insert, as just described, and oriented within the cutter such that the groove is widest at the cutting insert corner protruding the furthest from an axial location surface of the milling cutter.